1. Field of the Invention
The present invention relates to a method for the purification of marigold oleoresin and a purified marigold oleoresin obtained according to the method.
2. Description of the Prior Art
The recent scientific researchers have reported that lutein, a kind of carotenoid, is associated with risk reduction for age-related macular degeneration (AMD) caused by oxidative damage to macular area of retina (for instance, cf. non-patent literature 1), and that lutein is effective for prevention of arteriosclerosis, prevention of cataract or suppression of carcinogenesis and etc. (for instance, cf. non-patent literatures 2, 3 and 4). Thus, lutein is useful as a health food, a dietary supplement, a food color, a pharmaceutical color and a medicinal drug.
Lutein is contained in fruits such as oranges, peaches, papayas, prunes and mangos in the form of lutein-fatty acid ester and is also present in many flowers and vegetables, particularly in petals of marigold flowers remarkably. Marigold oleoresin is obtained in the manner that dried and ground marigold flowers are extracted with a hydrocarbon solvent such as hexane, petroleum ether and etc. or with a chlorinated hydrocarbon solvent such as dichloromethane and etc., then the solvent is removed from the extract. Most of the commercially available marigold oleoresin is in form of a solid or a paste having a high viscosity at room temperature, and the content of lutein-fatty acid ester in oleoresin is usually 14 to 20% as ester (for instance, cf. patent literature 1).
In order to use lutein as a health food and a dietary supplement, soft capsules which encapsulate the said marigold oleoresin with gelatin film are prepared. Particularly when the content is oily, it is said that soft capsules are the best of all in terms of easy handling due to the encapsulation of a liquid, protection and stabilization of the contents, homogeneity of the contents, masking of taste and odor, and their highly value-added impression (cf. non-patent literature 5, etc.). Soft capsules are usually produced by die-cutting method in which a fixed amount of contents infused between 2 sheets of gelatin is punched out. To produce soft capsules of the said marigold oleoresin, it is necessary to liquidize the said marigold oleoresin by heating and fusing, because the content must be a liquid having a viscosity capable of being injected by a metering pump, not more than 20,000 cps, for instance, according to a rotary die method (cf. non-patent literature 5, etc.).
However, there is no warming and heating process at a temperature of not less than 40° C. in the production of soft capsules, since gelatin, a raw material of soft capsule, loses its formability at a temperature of not less than 40° C. (cf. non-patent literature 5, etc.). Thus, it is difficult to heat, fuse, and fill in the said marigold oleoresin.
For this reason a method of liquidizing the said marigold oleoresin at room temperature by diluting and dissolving with the addition of an edible vegetable oil is taken. This method, however, has a disadvantage that the number of capsules taken per one time or one day increases because of the decrease in a lutein content per one capsule.
In addition to the above, a product forming a slurry at room temperature and containing not less than 15% of total carotenoids which is produced by suspending lutein-fatty acid ester extracted from marigold flowers with an edible vegetable oil is commercially available. However, this product has a disadvantage, in addition to the low content of lutein-fatty acid ester, that it entirely becomes solid and is impossible to be filled in soft capsules when it is heated and fused at about 80° C. for sterilization and then cooled to room temperature.
(Patent literature 1)
International Publication No.99/54408 pamphlet (p. 2, line 24)
(Non-patent literature 1)
The Japan Health Industry News, Co., Ltd. FOOD PROCESSING & INGREDIENTS, No.35, vol.4, p. 70 (2000)
(Non-patent literature 2)
Metamor Publishing Co., Ltd., Hoyoku Nishino and Khachik Frederic, NAZE MULTICAROTENE GA GAN WO YOKUSEI SURUNOKA (Why does multicarotene suppress cancer?) , p. 80 (1998)
(Non-patent literature 3)
Food Chemicals News Paper Inc., FOOD STYLE 21, No.3, vol.3, p. 52 (1999)
(Non-patent literature 4)
FFI Journal Editorial Committee, FOODS & FOOD INGREDIENTS JOURNAL OF JAPAN, No.191, p. 75–76 (March, 2001)
(Non-patent literature 5)
The Japan Health Industry News Co., Ltd., FOOD PROCESSING & INGREDIENTS, No.30, vol.2, p. 16 to 18 (1995)